User`s guide

202
CHAPTER 8 - CFW-08 OPTIONS AND ACCESSORIES
In the example the object value has not been represented as
hexadecimalvalue, but with correspondingASCIIcharacters.
For instance, for the object 00, the 'WEG' value has been
transmitted as being three ASCII characters, that as
hexadecimal have the values 57h (W), 45h (E) and 47h (G).
8.25.4
Modbus-RTU
Communication
Errors
Errors can occur duringthemessagetransmission on network,
or in the content of the received messages. Depending on the
error type, invertermayanswerornot tothe master:
Whenthemaster sendsa message toan inverterconfigured at
determinednetwork address, the inverterwillnot responseif:
Error in the paritybit.
Errorin the CRC.
Time out between transmitted bytes (3.5 times the time
requiredfor thetransmission of a 11-bit word).
In thecase of a successful reception ofthemessage,theinver-
tercandetectproblemsandsendanerrormessageto themaster
indicatingtheproblem that has been verified:
Invalid function (error code = 1): the requested function has
notbeen implementedfortheinverter.
Invalid data address (error code = 2): the data address
(register or bit) does not exist.
Data value invalid (error code = 3): this error occurs in the
following conditions:
-
Value is out ofpermitted range.
-
Writing in datathatcannot bechanged (onlyread register,
orregisterthatdoesnotallowchangingwithenabledinverter
orbits of logic status).
-
Writing in functionofthelogic command thathasnot been
enabledviaserialinterface.
Query (Master)
Field
Value
Slaveaddress
01h
Function
2Bh
MEI Type
0Eh
Read Code
01h
Object Number
00h
CRC-
70h
CRC+
77h
Response (Slave)
Field
Value
Slaveaddress
01h
Function
2Bh
MEI Type
0Eh
Read Code
01h
Conformity Level
51h
More Follows
00h
Next Object
00h
Number of Objects
03h
Object Code
00h
Object Length
03h
Object Value
‘WEG’
Object Code
01h
Object Length
0Ch
Object Value
‘CFW-08 7.0A’
Object Code
02h
Object Length
05h
Object Value
‘V3.77’
CRC-
C7h
CRC+
DEh
Table 8.30
- Message example using function 43